Study Promotes Use of Active Head Movement When Shifting Gaze to Rehab Vestibular or Cerebellar Dysfunction

Published on April 14, 2014

The results of research conducted by Ludgwig-Maximillians-Unversität München (LMU) neurologists could help pave the way for more effective rehabilitation of patients with vestibular or cerebellar dysfunction. The paper, which appears in the latest issue of Brain, reportedly investigates the significance of the vestibular system for optimizing motor coordination. A news release from LMU states that researchers focused on patients with bilateral defects in the vestibular system (a complete vestibulopathy) or lesions in the cerebellum. The study aimed to determine the role of the vestibular system in optimizing how humans direct their gaze.

Nadine Lehnen, MD, head of a research group based at LMU’s Center for Vertigo and Balance Disorders collaborated with colleague Murat Saglam, PhD, and Stefan Glasauer, PhD, professor, the Center for Sensorimotor Diseases at LMU, published the paper.

The release notes that the authors of the current study developed a mathematical model previously, which was designed to enable them to predict horizontal movements of the head and eyes in response to the presentation of an off-center stimulus.

Glasauer explains that, “When subjects repeated trials, healthy subjects are able to select the combination of eye and head movements that minimizes gaze shift variability.”

The researchers add that the subjects unconsciously choose the set of movements linked to the least error in the endpoint. Subjects can do this even when wearing a helmet with weights attached, the release says.

Yet, the release notes that patients exhibiting defects in the vestibular system or the cerebellum have greater difficulty in controlling the direction of gaze in response to changes in their environment.

“It turns out that information relayed from the balance organs to the vestibular system is essential for the optimization of gaze shifts,” Lehnen points out.

“In striking contrast, patients with cerebellar damage, can to a certain extent, learn to optimize certain parameters of head and eye movements, by adjusting the velocity of head movement for instance,” Glasauer adds.

In a scientific commentary on the study appearing in the print issue of Brain, Kathleen E. Cullen, McGill University in Montreal, emphasizes that the results reinforce the vestibular system’s critical role in optimizing voluntary movements.

Lehnen states that the researchers assume gaze shift control in patients who have sustained damage to the cerebellum and patients with incomplete vestibulopathies, “can be enhanced by a rehabilitation training based on active head movements.”

Since head movements provide vestibular feedback, generating sensorimotor error messages that trigger the ability to learn how to optimize the coordination of eye and head movements, the research indicates patients should be encouraged to actively move their heads when they shift their gaze, rather than working to hold them steady.